fix: adjust cron job time and add webp

.github/workflows/update-pr-data.yml

@@ -4,7 +4,7 @@ on:
   workflow_dispatch:
   schedule:
     # Runs on the 1 and 15 of each month at 00:00 UTC (see https://crontab.guru)
-    - cron: "0 0 1,15 * *"
+    - cron: "0 5 2,16 * 1"
     # Runs at 11pm on December 31st every year
     - cron: "0 23 31 12 *"
 jobs:
@@ -22,6 +22,10 @@ jobs:
         run: |
           # install pip=>20.1 to use "pip cache dir"
           python -m pip install --upgrade pip wheel
+      - name: Install webp
+        run: |
+          sudo apt-get update
+          sudo apt-get install -y webp
       - name: Install pyosmeta and run update contribs
         env:
           GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}